America's ABC News has predicted that Barack Obama will have enough delegates to secure the Democratic nomination after the votes from the final primary contests are counted tonight, based on the preliminary exit polls.
Obama, the first term Illinois Senator, is within 9 delegates of the 2,118 needed to clinch the Democratic nomination for president and is expected to win an additional number of delegates in the final primary contests and further superdelegate endorsements Tuesday.
Making history by becoming the nation's first African-American major party presidential nominee, Obama, emerges victorious from one of the longest and most closely found Democratic nomination fights in recent history.
The win is a huge accomplishment for Obama, 46,a first-term U.S. senator who, if he wins the White House, would be among the youngest presidents in U.S. history.
Delivering rousing speeches with a popular message of hope and change, Obama's insurgent candidacy inspired record-breaking campaign contributions, record turnout by black voters, and wide support from independents, liberals, young voters, and high-income, better-educated Democrats.
As the last day of a grueling, five-month Democratic primary battle fight came to a close, Sen. HIllary Rodham Clinton watched as the delegate count mounted for her opponent and told fellow New York lawmakers that she is open to being Obama's vice presidential candidate if he asks.
A year ago, the former first lady led every Democratic presidential candidate in the polls and was considered the party frontrunner with with big-money Democratic donors, the support of the Democratic establishment, and the backing of her husband, former President Bill Clinton.
But today Clinton, trailing Obama in delegates and her campaign in debt, spent much of the afternoon calling major donors and supporters from her home in Chappaqua, N.Y., in a last-ditch effort to gauge her support.
Speaking on a conference call her supporters she said she is "open" to being Obama's vice presidential candidate if he asks, a source on the call told ABC News' Rick Klein.
Clinton is planning to address supporters in New York tonight but is not expected to drop out of the race, a senior Clinton campaign official who is involved in drafting tonight's speech told ABC News' Kate Snow earlier Tuesday.
"She is spending the coming days making the case to superdelegates and unpledged delegates as to why she is the strongest candidate against John McCain," a Clinton campaign official said.
Clinton will give another speech after tonight where she will withdraw from the race, according to officials.
"This will not be the last speech she gives," a senior campaign official involved in writing Clinton's speech for tonight told Snow.
Obama is poised to pick up some of the 31 pledged delegates at stake in today's final primary contests in Montana and South Dakota, and saw an avalanche of superdelegates come his way over the last 24 hours including former President Jimmy Carter, and renowned civil-rights leader and House Majority Whip Rep. James Clyburn, D-S.D.
The Obama campaign pressed uncommitted superdelegates Tuesday to announce their support before the polls close tonight to allow him to emerge as the party's nominee without the appearance of it all coming down to the superdelegates.
Of the 796 Democratic superdelegates- party officials, members of Congress and state party leaders free to back any candidate -- less than 200 were still waiting to declare their support for either candidate when the day began.
"We've known for the last couple of months that even though Obama emerged as the front-runner, he was not going to be able to secure the nomination without the support of superdelegates," said Nathan Gonzales, political editor of the Rothenberg Political Report.
The Illinois senator is planning a victory speech tonight focused on the general election in the same Minneapolis arena where the Republican Party is holding its convention in September.
Obama spent the day putting the finishing touches on his speech and played basketball - a primary day tradition for him.
Aides said the Illinois senator's speech will look ahead to "a new phase, a new beginning" of the campaign and make an appeal for Democratic Party unity.
"Sen.Obama will walk on stage tonight as the nominee," an aide to Obama told ABC News' Sunlen Miller.
Trailing Obama in pledged delegates and superdelegates, and bleeding campaign money, pressure is mounting on Clinton to concede the race to Obama.
But this afternoon Democratic Majority Leader Harry Reid of Nevada told reporters that he encouraged uncommitted superdelegates in the Senate to hold off on endorsing immediately and to wait for results of tonight's primaries.
"Sen. Clinton needs to be left alone to get through the primary process and let it run it's course," Reid said.
Montana Sen. Jon Tester and South Dakota Sen. Max Baucus, said they would wait for tonight's primary results and vote with their state's voters.
While their phones have been burning up for months with calls from the candidates and former President Bill Clinton, many superdelegates were uncomfortable with their roles as potential kingmakers.
"For senators, you've got a race here between two of their colleagues, and at least one of them is coming back to the Senate, so I think their reluctance to pick a side is to maintain good relations," said Jennifer Duffy of the Cook Political Report.
Clyburn Tuesday urged fellow superdelegates to get off the fence.
"Sen. Obama brings a new vision for our future and new voters to our cause. He has created levels of energy and excitement that I have not witnessed since the 1960s," read Clyburn's statement released Tuesday.
Many prominent Democrats, including House Speaker Nancy Pelosi have urged fellow Democrats to vote the way their state does.
The role of superdelegates may be given more scrutiny after the grueling, neck-and-neck primary battle between Obama and Clinton.
The Democratic Party decided more than three decades ago that party leaders and former Democratic politicians should become the ultimate deciders in a tight race.
After the insurgent outsider campaigns of George McGovern and Jimmy Carter won the Democratic Party nominations in 1972 and 1976, many party officials felt the need to have a greater role in the nominating process.
Apart from convincing big numbers of undecided superdelegates to back her presidential bid, the only option left to Clinton is to push her fight to the Democratic convention in late August, a move opposed by party leaders eager to stop the infighting and start fighting against McCain.